1. Technical Field
The disclosure relates to a hub and drum assembly for a motor vehicle such as a tractor-trailer. Specifically, the disclosure relates to use of a shipping nut on the hub and drum assembly.
2. Description of the Related Art
Large motor vehicles and trailers, such as those used for shipping goods, contain hub and drum assemblies as part of their drive train. A typical drive train portion may include an axle, a spindle on the axle, a hub and drum assembly mounted on the spindle, and a wheel mounted on the hub and drum assembly. In some applications, there may be two wheels, an inner dual wheel and an outer dual wheel, mounted to a single hub and drum assembly. Flange nuts are generally used to mount the wheel or wheels to the hub and drum assembly, which usually includes studs for this purpose. For instance, a hub and drum assembly may have ten studs, over which the wheel will be placed and then secured by ten flange nuts. When two wheels are used, both wheels may be attached to the hub and drum assembly using only studs and flange nuts, or a system of studs, inner cap nuts, and outer cap nuts may be used. FIGS. 1 and 2 illustrate two different types of drive train portions.
FIG. 1 is an exploded view of a portion of a drive train assembled with flange nuts. Referring to FIG. 1, a portion of a drive train 10 may include a hub and drum assembly 11, an inner dual wheel 12, an outer dual wheel 13, and a plurality of flange nuts 14. The hub and drum assembly 11 includes a plurality of studs 15. When the drive train portion 10 is assembled, machined surfaces of the hub and drum assembly 11, the inner dual wheel 12, and the outer dual wheel 13 are brought into contact. Then the flange nuts 14 are threaded onto the studs 15 in order to secure all of the components in place relative to each other. It is critical that all of the components of the drive train portion 10 be correctly aligned with respect to each other in order to prevent excessive vibration and wear during operation.
FIG. 2 is an exploded view of a portion of a drive train assembled with inner and outer cap nuts. Referring to FIG. 2, a portion of a drive train 20 may include a hub and drum assembly 21, an inner dual wheel 22, an outer dual wheel 23, a plurality of inner cap nuts 26, and a plurality of outer cap nuts 27. The hub and drum assembly 21 includes a plurality of studs 25. Once again, when the drive train portion 20 is assembled, machined surfaces of the hub and drum assembly 21, the inner dual wheel 22, and the outer dual wheel 23 are brought into contact. Then the inner cap nuts 26, the outer cap nuts 27, and the studs 25 are threaded together in order to secure all of the components in place relative to each other. In this assembly it is also critical that all of the components of the drive train portion 20 be correctly aligned with respect to each other in order to prevent excessive vibration and wear during operation.
It is often the case that the hub and drum assembly is manufactured at one location, or by one manufacturer, and is then shipped to a second location and/or manufacturer to be assembled with some or all of the remaining drive train components. As the name suggests, the hub and drum assembly consists of two components; the hub and the drum. The hub and the drum are precisely machined to fit together such that the resulting assembly does not have excessive wear or vibration during operation. The hub and the drum are typically assembled together for shipping using two or more flange nuts. The hub and drum assembly is then shipped to another location and/or manufacturer as indicated above. Upon arrival at the second location, the shipping flange nuts have to be removed so that the wheel or wheels can be installed on the hub and drum assembly. This disassembly and reassembly of the hub and drum assembly can cause several problems. For instance, disassembling the hub and drum assembly, only to reassemble it again with the wheel exacts undesired labor costs. Plus, if the shipping nuts are not reused for installing the wheel, there is an unrecovered materials cost. The discarded shipping nuts can lead to workplace hazards if they are not disposed of properly. For example, loose shipping nuts may end up on the floor, presenting trip hazards for workers. Finally, if the hub and drum are not reassembled correctly when the wheel is installed, the resulting drive train may have excessive wear or vibration, leading to premature failure and hazardous conditions for the operator of the motor vehicle and other drivers on the road. Consequently, a hub and drum assembly that is stable during shipment but that does not have to be disassembled in order to install the wheel or wheels is desired.